As a program of a background art of a robot control apparatus for controlling a plurality of robots, there is a sequence program shown in FIG. 7. In a first sequence program shown in FIG. 7, a vertical column thereof is described with steps from step 1 through steps 2, 3 . . . , a horizontal column thereof is described with R1 item, R2 item and R3 item for respectively controlling robots RB1, RB2, and RB3. The same rows are the same steps and processed in parallel. A processing at each step is started after finishing to process one step before the each step.
Each R item comprises F column, operation column, part column, tool column, location column. F column displays presence/absence of a process continued from a preceding step, and when F column is described with an arrow mark, as in, for example, F column of step 2 of R3 item, it shows that a process of step 1 one step before thereof is continued to process also at step 2 (refer to Patent Reference 1).
Further, an explanation will be given of an apparatus of a background art for displaying a plurality of robot operation programs in reference to FIG. 8 through FIG. 10. In FIG. 8, a display region of a display screen of an operation program/state display portion is divided into a master task display region 71, a sub 1 task display region 72, a sub 2 task display region 73, a state display region 74, and a plurality of operation programs operated synchronizingly in accordance with a flowchart of FIG. 9 are displayed while cooperatively operating the operation programs as shown by FIG. 10. FIG. 10 shows the flowchart of FIG. 9 on a left side, shows a state display screen by respective operation programs of robots of FIG. 8 on a right side, and shows a behavior of controlling the display of FIG. 8 by the flowchart of FIG. 9 (refer to Patent Reference 2).
In FIG. 9 step 110 is a read operation where an input from the display/select is provided. At step 120 a determination is made as to which is the current task. If the current task is a master task, at step 130 a master task command execution process is executed. If the current task is a sub 1 task, at step 140 a sub 1 task command execution process is executed. Likewise, in the current task is a sub 2 task, at step 170 a sub 2 task command execution process is executed. In steps and 180, a determination is made if the tasks are in a cooperative execution mode. If the answer is positive then in steps 180 and 190, sub t task and sub 1 task command execution process is executed, respectively.    Patent Reference 1: JP-A-6-67709 (page 3, right row, line 46 through page 4, left row, line 17, FIG. 2)    Patent Reference 2: JP-A-11-48178 (page 3, right row, line 33 through page 4, left row, line 3, FIG. 2, FIG. 3, FIG. 6)